RU2641635C2 - System of capacitive sensors of measuring moisture in grain tank - Google Patents

Abstract

FIELD: measuring equipment.SUBSTANCE: each grain tank contains a data acquisition unit connected to a plurality of capacitive humidity measurement cables, wherein each comprises a plurality of sensor assemblies disposed along it in steps. Each sensor assembly comprises a pair of longitudinally extending capacitive plates of a capacitive humidity measurement sensor arranged in parallel and spaced apart to form a gap extending longitudinally between the capacitive plates. In the longitudinal gap between the capacitive plates circuit board is placed containing a microprocessor, memory and a temperature sensor. The outer housing provides a hermetic enclosure located around the circuit board, capacitive plates and a longitudinal section of humidity measurement cable that passes through the holes in each longitudinal end of the housing and condenses them.EFFECT: reducing the measurement error.20 cl, 14 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a system for measuring humidity in a grain tank and corresponding methods, and more particularly to cables, capacitive humidity measurement systems and methods for measuring humidity.

State of the art

This section provides information on the premises of the present invention, which should not necessarily be construed as prior art.

Capacitive moisture sensors are designed to determine the moisture content in the grain. However, in some cases, the grain should be in the gap between the capacitive electrodes or plates. Thus, such sensors are typically used for small grain samples transferred to a test facility, and they are not entirely suitable for measuring grain inside the grain tank.

In other cases, grounding electrodes are located at opposite ends of the tubular electrode of opposite polarity. This means that the capacitive clearances circle around the entire tubular sensor. Thus, to increase the adjacent measured grain volume, it is necessary to increase the diameter of the sensor. As a result of this, when used in large grain bins, so much downward force can be generated by the grain on the sensors that the roof structure of the grain bunker will not be able to withstand this force.

Disclosure of invention

That section provides a summary of the present invention, which is not an exhaustive disclosure of the entire volume or all of its features; also the features shown here do not represent the main aspects of the present invention.

According to one aspect of the present invention, there is provided a moisture sensor system in a grain silo comprising a data acquisition unit connected to a grain silo. The data acquisition unit comprises a microprocessor of the data acquisition device and a memory of the data acquisition unit connected to at least one capacitive cable for measuring moisture suspended in a grain tank. Each capacitive cable for measuring moisture contains an electric cable and many sensor nodes along the length of the electric cable. Each electrical cable further comprises a pair of main conductors enclosed in an insulating material and spaced apart from each other along a conductive plane passing through a pair of main conductors. A pair of secondary signal wires enclosed in an insulating material is located between a pair of main conductors. Each sensor assembly additionally contains a mounting plate located next to the insulating material, having the main dimensions along the length and width in the plane of the mounting plate parallel to the conductive plane. Each of the pair of capacitive plates extends generally perpendicular to the conducting plane. The first of the pair of main conductors is the ground conductor, and the first of the pair of capacitive plates is the ground plate located next to the ground conductor. The second of the pair of main conductors is the positive conductor, and the second of the pair of capacitive plates is the positive plate located next to the positive conductor. The outer casing provides a sealed enclosure around the circuit board, a pair of conductive plates and an adjacent portion of the electrical cable.

According to one aspect of the present invention, there is provided a moisture sensor system in a grain silo comprising a data acquisition unit connected to a grain silo. The data acquisition unit comprises a microprocessor of the data acquisition device and a memory of the data acquisition unit connected to at least one capacitive cable for measuring moisture suspended in a grain tank. Each capacitive cable for measuring moisture contains many sensor nodes located at a predetermined step along the electric cable, through which the sensor nodes are connected in parallel to the data acquisition unit. Each sensor node contains a microprocessor of the sensor node and a sensor node memory connected to a temperature sensor, a reference capacitive sensor and a capacitive humidity measurement sensor. Each sensor node further comprises a pair of longitudinally extending capacitive plates of a capacitive humidity measuring sensor located parallel and at a distance from each other to form a gap extending longitudinally between the capacitive plates. A longitudinally extending piece of cable for measuring moisture is located in the longitudinal gap between the capacitive plates. A circuit board containing the microprocessor of the sensor unit, the memory of the sensor unit and the temperature sensor is located inside the longitudinal gap between the capacitive plates and next to the length of the cable for measuring humidity. Each sensor assembly additionally contains an outer casing, hermetically sealed cable for measuring moisture at each longitudinal end of the casing with the formation of a sealed enclosure surrounding the circuit board, capacitive plates and a longitudinal length of cable for measuring moisture. An electric cable passes through the holes made in each longitudinal end of the housing and seals them.

Other applications will become apparent after reading the description herein. The description and representative examples in this brief disclosure are for illustrative purposes only and are not intended to limit the scope of the present invention.

Brief Description of the Drawings

The figures provided herein illustrate only selected embodiments, and not all possible implementations, and are not intended to limit the scope of the present invention.

In FIG. 1 is a perspective view of a capacitive humidity sensor system in a grain bin in accordance with the present invention;

in FIG. 2 is a perspective view showing the distribution of capacitive cables for measuring moisture inside the grain bin of the system of FIG. one;

in FIG. 3 is a perspective view of a sensor assembly of a capacitive cable for measuring moisture according to FIG. 2;

in FIG. 4 is a perspective view of a sensor assembly of a capacitive cable for measuring moisture according to FIG. 3, where half of the body is not shown to visually display its longitudinal dividing line;

in FIG. 5 is a perspective view of a sensor assembly of a capacitive cable for measuring moisture according to FIG. 3 without housing;

in FIG. 6 is a perspective view of a sensor assembly of a capacitive cable for measuring moisture according to FIG. 3 without housing and capacitive plates;

in FIG. 7 is a perspective view of the electric cable of the sensor assembly of the capacitive cable for measuring humidity according to FIG. 3;

in FIG. 8 is a block diagram of a circuit board of a sensor assembly of a capacitive cable for measuring moisture according to FIG. 3;

in FIG. 9 is an electrical diagram of a circuit board according to FIG. 7;

in FIG. 10 is a block diagram of a main data acquisition cycle by a data acquisition unit from sensor nodes and data transmission from the main system controller according to FIG. one;

in FIG. 11 is a flowchart of the main cycle of data collection and sending by the microprocessor of the sensor unit in response to a polling request from the system data acquisition unit according to FIG. one;

in FIG. 12 is a structural map of the placement in the memory of the source data of the main controller of the system according to FIG. one;

in FIG. 13 is a graph of capacitive variation as a percentage of the immersion depth of the sensor assembly in grain; and

in FIG. 14 is an image on a controller screen showing a radial arrangement of cables for measuring moisture in a grain bin and moisture content data for a selected cable for measuring moisture.

In several figures, corresponding parts are indicated by corresponding reference numerals.

The implementation of the invention

Exemplary embodiments will now be described in more detail with reference to the accompanying figures. Various representative details are set forth in the examples of embodiments described herein, for example, examples of representative components, devices, and methods to provide a thorough understanding of embodiments of the present invention. Those skilled in the art to which the present invention relates will understand that the use of characteristic details is optional, that examples of embodiments may be implemented in various ways, and that none of them should be construed as limiting the scope of the present invention. In some examples of embodiments, well-known processes, well-known device designs, and well-known technologies are not described in detail.

The terms used herein are intended only to describe specific examples of embodiments and are not limiting. As used herein, the terms in the singular include the plural, unless the other is clear from the context. The terms “comprises”, “comprising”, “including” and “having” are inclusive and therefore include the presence of the indicated features, integers, stages, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, stages, operations, elements, components and / or groups thereof. The stages of the method, processes and operations described in this document should not be construed as such, the implementation of which must necessarily be carried out in a strictly described or shown order, unless otherwise specifically dictates the execution order. You must also understand that additional or alternative stages can be carried out.

If it is indicated that the element or layer is “on”, “engaged with”, “connected to” or “mated with” another element or layer, this means that it can be located directly on, engaged, connected or mated with another element or a layer, or intermediate elements or layers may be present. Conversely, if it is indicated that the element is “directly on”, “directly engaged with”, “directly connected to” or “directly connected to” another element or layer, then intermediate elements or layers may be absent. Other terms used to describe the interaction between elements must be interpreted as an image of the interaction (for example, “between” and “directly between”, “near” and “directly next”, etc.). As used herein, the term “and / or” includes any and all possible combinations of one or more of the combined listed elements.

Although the terms are first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or regions, these elements, components, regions, layers and / or regions should not be limited by these terms. These terms can only be used to distinguish between one element, component, region, layer or region and another region, layer or region. As used herein, terms such as “first,” “second,” and other numerical terms do not imply sequence or order unless clearly indicated in context. Thus, the first element, component, region, layer, or region described later may be called the second element, component, region, layer, or region without departing from the ideas of the exemplary embodiments.

Terms indicative of spatial position, such as “internal,” “external,” “below,” “below,” “lower,” “above,” “upper,” and the like, may be used herein to simplifying the description of the relationship of one element or sign and another element (s) or sign (s), as shown in the figures. Terms indicative of a spatial position may encompass various orientations of the device during operation or operations in addition to the orientation depicted in the figures. For example, if the device in the figures is turned upside down, the elements described using the term “below” or “below” with respect to other elements or features, in this case will be oriented “over” other elements or features. Thus, an example of the term “under” can encompass both an orientation above and an orientation below. The device may be oriented differently (rotated 90 degrees or in a different position), and determinants indicating a spatial position used in this document should be interpreted accordingly.

In FIG. 1 is a block diagram of a system 10 for collecting moisture content data from a plurality of grain bins 12. There may be a plurality of grain bins 12 at a farm or receiving station, controlled by one main controller 14 containing a microprocessor 16, memory 18 and display 20. All the memory described herein, including memory 18, is a computer-readable long-term storage device. The main controller 14 communicates with each grain bin 12 through the wireless nodes 22, 24. For example, the wireless node 22 may be an 802.15-based module, and each wireless node 24 may include a PIC 18F2620 microprocessor.

The wireless node 24 of each grain bin provides input and output communication channels between the main controller 14 and the data collection unit 26 containing the microprocessor 28 and the memory 30. A plurality of moisture measurement cables 32 of each grain tank 12 are connected to the data collection unit 26 containing the microprocessor 28 and memory 30. Each humidity measurement cable 32 contains a plurality of sensor assemblies 34 arranged in steps along the length of each cable 32. Each sensor assembly 34 of each cable 32 has a parallel electrical connection to block 26 data collection.

Humidity measurement cables 32 are spaced apart from each other throughout the interior of the grain bin 12, as shown in FIG. 2. It should be understood that FIG. 2 is schematic for ease of understanding. Each moisture measuring cable 32 is physically suspended, as usual, from the roof structure of the grain bin 12 and is held by it. Similarly, the data collection unit 26 connected to the grain tank 12 may be located above the grain storage area, so that the grain in the grain tank 12 does not create substantially any downward force acting on the data collection unit 26. For example, the data collection unit 26 may be attached to the roof structure outside the grain bin 12 or from inside the grain bin 12 near the top of the roof structure.

According to FIG. 3-7, each moisture measurement cable 32 contains an electric cable 36. The electric cable 36 contains a pair of main conductors 38 and 40. For example, the main conductor 38 can provide grounding with the main conductor 40 having opposite polarity. The main conductors 38, 40 are spaced apart along a conductive plane CP passing through the conductors. Between the main conductors 38, 40 is a pair of communication signal wires 122. The conductors 38, 40 and signal wires 122 are isolated from each other and from the environment by means of an insulating material 42. The overall cross-sectional shape of the electric cable 36 is generally rectangular, providing a greater distance or gap between the main conductors 38, 40 by placing each main conductor 38, 40 next to one of the short sides 35 of a rectangular cross section.

The sensor assemblies 34 also comprise a mounting plate 44 located along one of the long sides 37 of the rectangular cross section of the electric cable 36. The mounting plate 44 is generally flat and rectangular in shape with major dimensions in length and width in the plane of the mounting plate BP parallel to the conducting plane Wed A pair of opposing capacitive plates 46, 48 is arranged along the opposite sides forming the length L of the mounting plate 44. Opposite capacitive plates 46, 48 likewise extend along the corresponding length of the electric cable 36, next to each short side 35 of the rectangular cross section of the electric cable 36. The mounting plate 44 contains circuit board components 45 mounted thereon, such as a microprocessor of a sensor assembly and memory.

A flat ground plate 46 is located next to the corresponding length of the main ground conductor 38, and a plate 48 of opposite polarity is located next to the corresponding length of the main conductor 40 of the opposite polarity. Opposite capacitive plates 46, 48 can be arranged generally perpendicular to the conductive plane CP and the plane of the circuit board BP. Each capacitive plate 46, 48 can extend only outside the plane extending along the inner edge of the main conductor 38 or 40 and perpendicular to the conducting plane CP and the plane of the circuit board BP.

Power to the circuit board 44 is supplied through the main conductors 38, 40. Data is transmitted from and to each sensor unit via signal wires 122. A portion of the insulating material 42 is removed to provide electrical connection between the signal wires 122 and the main conductors 38, 40 with the circuit board 44 by means of spring-loaded plunger contacts. The electrical insulation material 42 can be removed by heating, mechanical abrasion, or in another way to create a pair of main cavities 52, providing access to the main conductors 38, 40, and at least one secondary cavity 54 that opens the secondary conductors 122.

The mounting plate 44, the capacitive plates 46, 48, and the corresponding portion of the electric cable 36 are enclosed in a two-piece housing 50, creating a sealed interior space and forming each sensor assembly 34. The interior space may be filled with foam or gel to protect the mounting plate 44 and the corresponding Sensor components against vibration, shock, and unwanted environmental elements such as moisture. The halves of the housing 50 can be joined together using threaded fasteners. Next, details of the circuit board 44 will be described.

In FIG. 8 is a block diagram of a circuit board 44 for each sensor assembly 34. Each sensor assembly 34 uses a microprocessor 100, which can be implemented using a PIC16F54 microprocessor device. The microprocessor 100 comprises an internal addressable memory 102. The system clock 104 may be implemented with an appropriate chip to control the clock frequency of the microprocessor device. For a microprocessor device such as the PIC16F54, you can use the corresponding 4 megahertz crystal. Each sensor assembly 34 also comprises a power supply and controller circuit 106, through which a nominal operating voltage of 5 V DC is applied to various components of the humidity measurement sensor. The power supply and regulator circuit 106 can be implemented by means of a voltage regulator circuit LN78L05ACZ, the input voltage of which is 15 VDC, and the output is regulated 5 VDC.

The microprocessor 100 collects data indicating the moisture content, as well as data indicating the temperature. The moisture content data is generated by a capacitive measuring plate 108, which changes the capacitance in proportion to the moisture content. Capacitive measuring plate 108 corresponds to opposite capacitive plates 46 and 48. By measuring changes in capacitance, moisture content data is obtained.

More specifically, a capacitive measuring plate 108 is included in the oscillation circuit 112 through an electric switch 110. Changes in capacitance can cause a change in the oscillation frequency of the oscillatory circuit. The microprocessor 100 performs measurements of the oscillation frequency and thus collects data indicating the moisture content.

To ensure the accuracy of the moisture content readings measured by changing the capacitance, the humidity and temperature sensor of the assembly contains a reference capacitor 114, which can be included in the oscillating circuit 112 (instead of the capacitive measuring plate 108) through the switch 110. As shown, the microprocessor 100 controls the switch 110. Thus, the microprocessor 100 determines whether the oscillating circuit 112 will oscillate with a frequency specified by the capacitive measuring plate 108 or the reference capacitor 114.

Temperature data is provided by the grain temperature sensor 116. The temperature sensor 116 is connected to the microprocessor 100 through an analog-to-digital converter 118.

The microprocessor 100 collects data on the moisture content and temperature from these respective sensors and transmits the values of the collected data through the RS-485 transceiver 120. More specifically, the values of the data collected by the microprocessor 100 are stored in the memory 102, and then, in accordance with the request, are sent via a transmission line (TX) to the RS-485 transceiver 120. Requests for the transmission of such data are sent from the RS-485 transceiver 120 via the receive line (RX) to the microprocessor 100. Data is transmitted by the RS-485 transceiver 120 through a balanced cable (with two data lines) cable 122 containing the data input / output line A and line B input / output data. According to the RS-485 protocol, lines A and B do not coincide in phase with each other by 180 °, so that interference in both lines from the same interference source will be effectively cut off.

According to FIG. 9, data lines A and B are connected to respective data lines of similarly configured humidity sensors in parallel through a connector or plunger contacts 131 to form a multi-point communication line with distributed sensors located in a grain bin, as described above. To ensure independent activation and interrogation of each of the sensors for data collection, the microprocessor 100 of each sensor is programmed to respond to a unique identification address. When the system needs to receive data from a specific sensor, a message through a balanced cable 122 and through an RS-485 transceiver 120 is sent to a microprocessor 100, which then responds to a data request by receiving measurements from humidity sensors and from temperature sensors and transmitting them back through the RS transceiver interface -485. As will be described below, each individual sensor is activated only when there is a need for sensor readings. Otherwise, the sensor is disabled. Connector 133 is for programming the microprocessor 100, for example, to provide software updates.

One of the advantages of the cable system of humidity and temperature sensors is that each sensor collects data on moisture content and temperature from different points in the grain tank, and each sensor transfers raw measurement data (unique for this point inside the tank) to a multifunctional processing system for analysis. In order to collect such a quantity of data in a compact and economical package, in the circuit of the humidity measurement sensor shown in FIG. 8 and 9, several chain enhancements are used to help reduce size, cost, and power consumption while providing high reliability and accuracy.

A microprocessor 100, together with a system clock 104 and an associated RS-485 transceiver 120, is shown together with connection leads. It should be noted that this circuit 106 of the power source and the regulator contains a 5 V bus 124, which supplies 5 V adjustable to several components of the circuit, for example, to the microprocessor 100 to its output of 126 power supply to 5 V. A similar output of 128 power supply to 5 It supplies an adjustable 5 VDC to transceiver 120 RS-485. Other 5V power supply connections are also shown in FIG. 8, however, will not be further described.

15 V DC is supplied to the power supply and regulator circuit 106 via a 5 V rail 130. The bus 130 is located on the unregulated side of the power supply, to which a voltage of 15 V DC is supplied through the connector or plunger contacts 131. It should be noted that an unregulated supply voltage of 15 V is also supplied to other points in the circuit, for example, to terminal 132 of a 15 V power supply of temperature sensor 116.

In order to save energy, when a specific sensor is not accessed, a supply voltage of 15 V may not be supplied to the main controller. In the disconnected state, voltage is not supplied through the connector or plunger contacts 131 and the entire circuit shown in FIG. 8 and 9, de-energized. When 15 V is supplied via connector 131, power is supplied to the entire circuit. In order to provide power to the microprocessor in a controlled manner, a voltage reduction sensor 134 is included in the circuit. The undervoltage sensor responds to the 5-volt bus when it reads on the output of the 5 V power supply at terminal 136 and sends a reset signal to the microprocessor 100 after the voltage levels stabilize to the proper value of 5 V.

As described with reference to FIG. 8, oscillation generator 112 measures the capacitance values of the measuring plate 108 and the reference capacitor 114. Such capacitors may be precision capacitors, such as NPO ceramic capacitors. According to the illustrated embodiment, the oscillation circuit 112 is made using a pair of Schmidt trigger circuits 138, which create oscillations at a nominal frequency of approximately 300 kHz; The exact frequency varies depending on the set capacitance value. In this regard, the measuring plate 108 and the reference capacitor 114 (in this case, a pair of parallel capacitors) are alternately turned on and off in the oscillating circuit 112 through the switch 110 with microprocessor control. The switch 110 is made using a pair of bi-directional analog switches, which are controlled based on the value of the data supplied to the wire 140 from the microprocessor 100.

When the microprocessor 100 receives a command to read and provide data, by means of a command issued by the RS-485 transceiver 120, the microprocessor reads the frequency of the oscillatory circuit, while the reference capacitor 114 is connected to the circuit, and then changes the settings of the switch to read the frequency of the oscillator, while the capacitor 108 of the measuring plate is included in the oscillatory circuit. Both data values are received and transmitted via the RS-485 transceiver 120 each time a data request is received. Thus, the moisture content is measured (based on readings obtained with the capacitive measuring plate 108). Any spontaneous movement in the circuit or other measurement aberrations caused by temperature changes or component aging should be measured and compensated for using readings obtained from the reference capacitor 114. When both readings are obtained, the humidity measurement sensor provides very accurate and reliable data on the installed moisture content.

According to the illustrated embodiment, the oscillation circuit 112 oscillates at a nominal frequency of approximately 300 kHz. As long as the use of a microprocessor with high-speed capabilities sufficient to directly calculate the oscillations at such a cycle time remains possible, such microprocessors will be considered expensive. Thus, in the embodiment shown, a cyclic measurement technique is used, according to which the real-time clock function of the microprocessor device is used. To measure the frequency of the oscillation generator, a register or memory cell in the microprocessor 100 is programmed to increase the increment counter for each input pulse coming from the oscillating circuit, starting from zero and up to register overflow. The microprocessor is programmed to track and record the number of times such an overflow of the register within a given period of time, and then also to read the value that is currently in the register, after the expiration of the period of time to perform the measurement. Then, the registered number of overflows and the current value of the register at the end of the measurement cycle are used together to calculate the frequency of the oscillation generator, and then this value is converted into equivalent readings of the moisture content using the capacity-humidity transformation.

Temperature measurements are performed by a temperature sensor 116, which provides an analog value that can be converted to a digital value using an analog-to-digital converter 118. As long as there are previously provided analog-to-digital conversion devices that can be used to perform this function, the embodiment shown provides cost savings due to the implementation of analog-to-digital conversion using a comparator 142, designed to compare the output value of the sensor 116 temperatures with a ramp ramp across the capacitor 144. Essentially, the capacitor 144 is equipped with a stabilized current source 146 implemented by a pair of transistors, which may be precision transistors. The stabilized current source thus supplies a controlled speed to the capacitor 144, so that the voltage across the capacitor 144 increases linearly from zero to the voltage of the power supply (plus 5 V) to form a sawtooth characteristic. Using an electric switch 148, the microprocessor 100 periodically closes the capacitor 144 to earth, thereby resetting the voltage of the capacitor to zero, again starting a sawtooth shape. After opening, the voltage across the capacitor 144 increases at a constant speed due to the stabilized current source 146, which makes the voltage across the capacitor 144 a reference source with which the comparator 142 compares the output of the temperature sensor 116.

According to FIG. 10, a main loop is provided for collecting and transmitting data from sensor nodes 34 to a data collection unit 26. In block 200, the data collection block expects to receive a request for sensor data from the hopper from the main controller 14. In block 202, after receiving the request, the identifier of the active cable is first set to the maximum value. For example, if there are 19 cables in the grain tank, then the active cable identifier is set to 19. At block 204, microprocessor 28 supplies power to the active cable 32 corresponding to the specified cable identifier. At a block 206, the microprocessor 28 awaits initialization of the sensor nodes 34 on the active cable 32.

In block 208, the identifier of the active sensor node is set to the maximum value. For example, if there are 24 sensor nodes on the humidity cable 32, the sensor node identifier is set to 24. At block 210, the attempt request counter is set to 1, indicating that the first data request is being accessed for the sensor node 34. In block 212, the request data is sent to the active sensor node. If in block 214 the data arrives in block 26 for collecting data for a predetermined period of time, then in block 216 the data is checked for compliance.

If at block 214 no data is received within a predetermined period of time or data is not confirmed, the logic of the microprocessor 28 proceeds to block 218 to determine whether the counter of requests for attempt exceeds the set value corresponding to the maximum value of the number of attempts. If not, then in block 220, the attempt request counter is increased by one, and the logic returns to block 212 to send the next data request to the touch node that is being accessed; that is, in the active sensor node on the active cable for measuring moisture in the studied grain bin.

If the data is received in block 214 and the correspondence is confirmed in block 216, then the data is sent through the data collection block 26 and the wireless nodes 11 and 24 to the main controller 14 for processing in block 222. After the microprocessor 100 determines in block 218 that the number of requests the attempt exceeds the preset maximum value, in block 234 the error value of the incorrect data for each temperature sensor, reference capacitance, and humidity is transmitted to the active sensor node, and the error value is sent to the main controller in block 222.

In block 224, microprocessor 28 determines the presence of additional sensor nodes on the active cable from which data was not collected. If such nodes are present, then in block 226 the identifier of the active node is reduced by one, and the logic returns to block 210 to set the attempt counter to 1 for the new active sensor node. If not, then at block 228, power to the active cable is cut off.

At a block 230, a determination is made of the presence of additional cables for measuring moisture in the grain bin from which data were not collected. If such cables are present, in block 232 the value of the active cable identifier is reduced by 1, and in block 204, the cable corresponding to the reduced cable identifier is supplied with power until the previous active cable is de-energized. If not, then power to the moisture measurement cable is not supplied and in block 200, the data collection unit 26 simply waits for another data request.

According to FIG. 11, the main cycle is performed for each sensor node of the microprocessor 100. When power is supplied to the cable 32 for measuring moisture, in block 250 the microprocessor 100 is set to the listening mode of the packet with the header. If it is determined that a packet with a header is not defined in block 252, then the microprocessor continues to listen to the packet with a header in block 250. If a packet with a header is determined in block 252, then the packet is received in block 254 and a determination is made in block 256 of whether the packet with the header is a set of data request bits. If not, then the microprocessor 100 returns to listening at block 250. If so, then at block 258, the identifier of the active node is retrieved from the packet with the header. If the extracted node identifier matches the node identifier in block 260, then in block 264, temperature, raw capacity data and moisture content data obtained by changing the capacity are collected and sent to data collection unit 26.

As follows from the above description of FIG. 10 and 11, a plurality of nodes 34 of capacitive humidity measuring sensors are located inside the grain tank 12 on a plurality of moisture measuring cables 32. Power is supplied to a selected one of the plurality of moisture measurement cables 32, without activating the plurality of nodes 34 of the capacitive humidity sensors on the selected moisture measurement cable 34. Powered but inactive sensor nodes 34 do not essentially consume current. In particular, due to the supply of power to only one cable 32 for measuring moisture at a time, inactive sensor nodes 34 do not generate unwanted heat, which can adversely affect the data being collected.

The selected one of the plurality of nodes 34 of the capacitive humidity measurement sensors on the selected moisture measurement cable 32 is activated. The moisture content data obtained by changing the capacitance and the temperature data are provided by the activated sensor assembly 34 located on the selected moisture measurement cable 32. The selected one of the plurality of nodes 34 of the capacitive humidity measurement sensors returns to the inactive state. The activation of the next one of the plurality of nodes 34 of the capacitive humidity measuring sensors located on the selected cable 32 for measuring moisture is carried out until each of the sensor nodes 34 located on the selected cable 32 is separately activated. The power supply is cut off at a selected one of the plurality of humidity cables 32. Power is supplied to the next selected one of the plurality of cables 32 for measuring moisture until each of the plurality of cables 32 for measuring moisture is separately powered and each of the sensor units 34 is separately activated and data is not collected from it.

As indicated above, the data sent to the main controller 14 from each sensor node is raw data that has not yet been converted to a moisture content value. One advantage of this is that it is not necessary to provide the data collection unit 26 with sufficient memory and power to convert the raw data to a moisture content value. Another advantage is that the data collection unit does not need information about the type of grain stored in the grain tank, since the information is usually already stored in the main controller for other purposes.

A data structure map of a portion of the memory 18 of the main controller 14 is shown in FIG. 12. Raw data collected from all the sensor nodes 34 of the grain bin 12 can be stored in the memory 18 of the main controller, as indicated in this data structure map. The raw data contains temperature data, initial capacity data, and moisture content data obtained by changing the capacity. Since the original raw data from each sensor node is copied to the memory 18 of the main controller, there is no need to process any of these raw data in the sensor nodes 34 or data collection unit 26. This memory and conversion power needed to process the raw data should only be present in the main controller; they do not need to be duplicated in the sensor nodes 34 or data collection unit 26.

One way to supply the system with the software necessary to convert the raw data into the calculated moisture content of each sensor is to use a curve that displays the ratio of the measured capacitance to the reference capacitance relative to the measured moisture content. A temperature coefficient such as ((T-80) × 0.046), where T is the measured temperature, can be used to calculate the temperature difference. For this curve you can get the formula. This formula may vary for different grains. One example of a formula may be:

Humidity% = (A × ((B- (C _m / C _r )) ^C ) - ((T-80) × 0.46),

where A, B and C are the constants obtained experimentally for each type of grain;

C _r - raw source capacitive data;

C _m - raw measured capacitive data; and

T is the temperature in degrees Fahrenheit.

After obtaining the formulas for each type of grain, they can be programmed into the main controller 14 for use in converting raw data into calculated data on the moisture content. Thus, the calculated value of the moisture content is determined by the main controller 14 depending on these three pieces of raw data that can be stored in the memory 18 in accordance with the data structure map, an example of which is shown in FIG. 12.

Another option is to provide lookup tables for each type of grain. For example, a look-up table comparing the ratio C _m / C _r with the value of the initial moisture content can be programmed into the main controller 14. A look-up table for controlling the temperature can be entered in the memory 18 of the main controller to adjust the initial value of the set moisture content depending on temperature data.

The physical location of each sensor node in the grain bin is important. Thus, as shown in FIG. 12, a map with a single data structure can contain both the address of the sensor node and the physical location coordinates of the various sensor nodes 34 in the grain bin 12. Such location information can be entered into the memory 18 of the main controller during the initial installation and configuration of cables for measuring humidity in grain hopper.

One reason why the physical location of each sensor assembly is important is to allow the determination of the depth of grain in the hopper 12 and the depth of the location of the sensor nodes 34 below the grain surface. If there is no grain around a particular sensor unit 34, then the system 10 will record the value of the absence of nearby grain, for example, zero, for any data that falls outside the specified range for the humidity obtained by changing the moisture capacity. For example, the ratio of the measured capacitance to the reference capacitance, which is lower than 3% for the sensor assembly 34, may indicate that there is no grain near this sensor assembly 34. As a result, the main controller 14 can determine the grain height in the grain bin 12 based on such abnormal readings. For example, if the sensor nodes 34 are located four feet apart, the system 10 may assume that the fill height of the grain tank on the cable 32 for measuring moisture is two feet lower than the sensor node located at the lowest point, returning the value of the absence of grain nearby.

Such grain fill height information can be used to determine the required air flow rate as part of a variable speed fan control method, as described in US Pat. No. 13/180797 to the same applicant, filed by Bloemendaal et al. July 12, 2011 and entitled "Bin Aeration System", which is incorporated herein by reference in its entirety.

Such grain height information can also be used to apply the grain depth correction factor to calculate the moisture content determined for each sensor unit 34. In the above example, the equation for calculating the moisture content ((T-80) × 0.46) is a correction temperature coefficient. The compaction correction factor can also be used based on experimental data obtained which can form a curve similar to the curve shown in FIG. 13. For example, the pressure variation curve of the capacitance can be divided into three areas: the first steep area for correction data on the moisture content calculated by means of sensor nodes located at a shallow depth (region A in Fig. 13); an area with an average slope for correcting moisture content data calculated by means of sensor nodes located at an average depth (region B in FIG. 13); and a low slope area for correcting moisture content data calculated by deeply located sensor nodes (region C in FIG. 13). An alternative to the microprocessor of the main controller programmed for applying such slope-based formulas to correct the compaction is to provide a reference table in the memory of the main controller for use by the microprocessor to adjust the moisture content depending on the depth calculated for each sensor unit 34.

Another reason why the physical location of each sensor node is important is to allow the graphical display of data so that a site or nest with high moisture grain can be detected by the user. In FIG. 14 shows a graphic screen that can be selectively displayed on the display 20 of the main controller 14. The left side of the screen of the display 20 shows a schematic plan view showing the radial or horizontal arrangement of moisture measurement cables 32 in the grain tank 12. In this embodiment, the grain tank 12 contains 6 cables 32 for humidity measurement, arranged to form a triangular configuration of 3 cables, and an external triangular configuration of 3 cables, inverted relative to the inner gon. The plan view also shows an indicator for determining the position and orientation, which in this case means “north”.

The user can select a separate cable 32 for displaying moisture content data for the sensor nodes 34 of the selected cable 32. For example, each of the blocks 60 can be represented by an on-screen button that the user clicks on to select the corresponding cable 32 for measuring moisture. Alternatively or additionally, the user may enter via the keyboard a number corresponding to the required cable 32 for measuring humidity to select the display of the calculated moisture content data of the corresponding cable 32 for measuring humidity. Once selected, field 60 of the selected cable may be highlighted in various colors.

On the right side of the display screen is a perspective view 62 with a remote section showing the calculated moisture content data values for the selected cable 32 shown on the left of the display screen 20. The moisture content data graph also contains an indicator of the upper grain surface 64 obtained on the basis of data received from all nodes 34 of the humidity measurement sensors in the grain tank 12. The figure graphically shows data on the moisture content in a vertical orientation, which essentially corresponds to the vertical position ju sensory nodes. Thus, the grain height or grain depth can be plotted along the vertical axis, and the calculated moisture content can be plotted along the horizontal axis.

The cable selection image 56 on the left and the moisture content data graph 62 on the right can appear on the same screen of the display 20 at the same time, as shown in FIG. 14. Alternatively, the main controller 14 may provide the user with the ability to switch between windows with a cable selection image 56 and a moisture content data graph 62 sequentially in the same space of the display screen.

The physical location of each sensor assembly 34 also plays an important role in providing corrective action in relation to the problem area or socket. For example, a problem grain may be selectively removed from a grain bin for drying. One exemplary system capable of facilitating such selective removal of a nest with grain from a grain bin is disclosed in US Pat. No. 12 / 827,448 to the same applicant, filed by Niemeyer et al. June 30, 2010 and entitled "Circular Bin Unload System and Method", which is incorporated herein by reference in its entirety. For example, instead of sequentially opening all the compartments in the floor to empty the entire grain tank, you only need to open the compartments in which there is a problem area or nest through which the grain will be removed. In this way, the grain presenting the problem can be selectively removed from the grain storage bin. The removed grain can be passed through a grain dryer and returned to the hopper. This can be helpful if the area or nest is near the bottom of the grain tank.

According to another example, if the problematic area or nest is at the top of the grain bin, only compartments located below the problematic area or nest will open. In this case, a sufficient amount of grain will be removed to form a lowered point in the surface of the grain embankment over the area or nest presenting the problem. In this way, a channel can be created for the low-resistance air flow passing through the problem area or socket, and fans and heaters can be used to pump air, preferably through the problem area or socket, to process it.

As another example, the grain bin can be ventilated by fans and heaters, if any. As indicated above, the surface of the grain embankment in the grain bin can be influenced to preferentially pass air through a problematic section or nest located in the grain bin. For example, the grain may be selectively removed from the grain bin through a system proposed by Niemeyer et al. and the above, to form a shorter channel for air flow through the nest in the grain embankment, which is a problem. Alternatively or additionally, the grain can be selectively added to the hopper using a grain feed distributor with a variable feed rate to provide in the same way a channel for air flow through the nest in the grain embankment, which is shorter than air channels that do not pass through the a nest problem in a grain mound. After the formation of a shorter air flow channel, preferably allowing air to pass through the problem area or nest, drying fans can be turned on to allow air to pass through the grain bin until the moisture level that presents the problem is eliminated.

The above description of embodiments is provided by way of example only. It is not intended to limit the scope of the present invention. The individual elements or features of a characteristic embodiment are not generally limited to this characteristic embodiment, but, if applicable, are interchangeable and can be used in a selected embodiment, not even indicated or described. It can also be changed in various ways. Such options should not be construed as falling outside the scope of the present invention, and all such modifications are included in the scope of the present invention.

Claims (34)

1. A sensor system for measuring moisture in a grain bin, comprising: a data collection unit connected to the grain tank and comprising a microprocessor of the data collection unit and a memory of the data collection unit connected to at least one capacitive cable for measuring moisture suspended in the grain tank; moreover, each capacitive cable for measuring humidity contains an electric cable and a plurality of sensor nodes along the length of the electric cable; wherein each electrical cable further comprises: a pair of main conductors enclosed in an insulating material and located at a distance from each other along a conductive plane passing through a pair of main conductors; a pair of secondary signal wires enclosed in an insulating material located between a pair of main conductors; moreover, each sensor node further comprises: a circuit board located next to the insulating material and characterized by major dimensions in length and width in the plane of the circuit board parallel to the conductive plane; a pair of capacitive plates, each of which extends away from the electric cable as a whole perpendicular to the conducting plane, the first of the pair of main conductors being a grounding conductor, and the first of a pair of capacitive plates is a grounding plate located next to the grounding conductor, the second of the pair of main conductors is a positive conductor, and the second of a pair of capacitive plates is a positive plate located next to the positive nym conductor; and an outer casing providing a sealed enclosure around the circuit board, a pair of electrically conductive plates and an adjacent portion of the electrical cable. 2. The moisture sensor system of the grain bin according to claim 1, wherein the housing contains non-conductive material, wherein any conductive material of the housing is electrically isolated from conductors, signal wires, a circuit board and capacitive plates. 3. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 1-2, in which the sealed casing is filled with gel-based material. 4. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 1-2, additionally containing a pair of main cavities in the insulating material, with each main cavity providing access to one of the main conductors; and further comprising a pair of plunger contacts, each plunger contact extending into one of the main cavities for electrically connecting the pair of main conductors to the circuit board. 5. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 1-2, additionally containing a secondary cavity in the insulating material, providing access to at least one of the secondary signal wires; and further comprising a pair of plunger contacts, each plunger contact extending into at least one of the secondary cavities for electrically connecting the pair of secondary signal wires to the circuit board. 6. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 1-2, in which the housing is characterized by the presence of an external tubular central part with an upper curved end surface, and the housing is formed by two halves of non-conductive material, mated along the Central dividing line that runs along the entire length of the sensor node in the longitudinal direction. 7. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 1-2, further comprising a main controller comprising a microprocessor of the main controller and a memory of the main controller, the main controller being connected to a data acquisition unit, the memory of the main controller being configured as a data structure containing grain type data, temperature data, raw source data about capacities, raw data on the moisture content obtained by changing the capacitance, data on the identification of the node, data on the physical location of the node and the calculated moisture content for each sensory node. 8. The moisture sensor system in the grain bin according to claim 7, wherein the main controller further comprises a display screen that selectively displays a graphical representation of the calculated moisture content for the selected sensor nodes in accordance with their location in the grain bin. 9. The moisture sensor system in the grain bin of claim 8, wherein the at least one moisture measurement cable is a plurality of moisture measurement cables, wherein a graphical representation of a plurality of moisture measurement cables is selectively displayed on a display screen according to their location in the grain tank, and a position indicator appears on the display screen to enable the user to select one of a plurality of moisture measurement cables. 10. A sensor system for measuring moisture in a grain bin, comprising: a data collection unit connected to the grain tank and comprising a microprocessor of the data collection unit and a memory of the data collection unit connected to at least one capacitive cable for measuring moisture suspended in the grain tank; moreover, each capacitive cable for measuring humidity contains many sensor nodes located at a predetermined step along the electric cable, through which the sensor nodes are connected in parallel to the data acquisition unit; moreover, each sensor node contains a microprocessor of the sensor node and a sensor node memory connected to a temperature sensor, a reference capacitive sensor and a capacitive humidity measurement sensor; moreover, each sensor node additionally contains a pair of longitudinally extending capacitive plates of a capacitive humidity measuring sensor located parallel and at a distance from each other with the formation of a gap extending longitudinally between the capacitive plates of the gap, and the longitudinal section of the cable for measuring humidity is located inside the longitudinal gap between the capacitive plates, and mounting the board contains a microprocessor of the sensor node, the memory of the sensor node and a temperature sensor located inside the longitudinal gap a gap between the capacitive plates and next to the length of the cable for measuring moisture; and each sensor assembly additionally contains an outer casing, hermetically sealed cable for measuring moisture at each longitudinal end of the casing with the formation of a sealed casing surrounding the circuit board, capacitive plates and a longitudinal length of cable for measuring moisture, the electric cable passing through the holes in each longitudinal end of the casing and compacts them. 11. The moisture sensor system in the grain bin of claim 10, wherein the electrical cable further comprises a pair of main conductors spaced apart from each other along a conductive plane passing through a pair of main conductors, the pair of secondary signal wires being located between the pair of main conductors ; wherein each of the longitudinally extending capacitive plates extends generally perpendicular to the conducting plane. 12. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, further comprising a pair of main cavities in the insulating material, each main cavity providing access to one of the main conductors; and further comprising a pair of plunger contacts, each plunger contact extending into one of the main cavities for electrically connecting the pair of main conductors to the circuit board. 13. The system of sensors for measuring humidity in the grain tank according to claim 12, further comprising at least one secondary cavity in the insulating material, providing access to a pair of secondary signal wires; and further comprising a pair of plunger contacts, each plunger contact extending into at least one secondary cavity for electrically connecting the pair of secondary signal wires to the circuit board. 14. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, in which the electric cable further comprises a pair of main conductors spaced apart from each other in the transverse direction, and a pair of secondary signal wires located between a pair of main conductors; moreover, a pair of main conductors contains a main ground conductor and a main conductor of opposite polarity, and a pair of longitudinally extending capacitive plates contains a ground capacitive plate and a capacitive plate of opposite polarity, and the ground capacitive plate extends along the side and outward from the ground conductor, located at a distance from the opposite conductor polarity, and a capacitive plate of opposite polarity runs along the side and out from an ovodnik of opposite polarity, located at a distance from the conductor with the polarity of grounding. 15. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, in which the housing contains non-conductive material, and any conductive material of the housing is electrically isolated from conductors, signal wires, circuit board and capacitive plates. 16. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, in which the sealed casing is filled with a gel-based material. 17. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, in which the housing is characterized by the presence of an external tubular central part with an upper curved end surface, the housing being formed by two halves of non-conductive material, mated along a central dividing line running along the entire length of the sensor assembly in the longitudinal direction. 18. The system of sensors for measuring humidity in the grain tank according to any one of paragraphs. 10-11, further comprising a main controller comprising a microprocessor of the main controller and a memory of the main controller, the main controller being connected to a data acquisition unit, the memory of the main controller being configured as a data structure containing grain type data, temperature data, raw source data about capacities, raw moisture content data obtained by changing the capacitance, node identification data, node physical location data, and calculated moisture content for each sensor node. 19. The moisture sensor system in the grain bin according to claim 18, wherein the main controller further comprises a display screen that selectively displays a graphical representation of the calculated moisture content for the selected sensor nodes in accordance with their location in the grain bin. 20. The moisture sensor system in the grain bin of claim 19, wherein the at least one moisture measurement cable is a plurality of moisture measurement cables, wherein a graphical representation of a plurality of moisture measurement cables is selectively displayed on a display screen according to their location in the grain tank, and a position indicator appears on the display screen to enable the user to select one of a plurality of moisture measurement cables.

Images